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We appreciate the interest of Drs. Manescal and Dubourg in ourarticle and we are indebted for their constructive comments.In our study most of the data were     

Gene expression profiling in rheumatoid arthritis: current concepts and future directions

Over the last years microarray technologies have generated new perspectives for the high-throughput analysis of biological systems. Nowadays, it is possible to monitor thousands of genes in a single experiment. This molecular profiling technology combined with standardised and validated clinical measurements can allow a more precise characterisation of a patient's phenotype, and may lead to the design of therapeutic protocols and procedures better tailored to an individual patient's needs. In this report we provide an overview of expression profiling studies in rheumatoid arthritis (RA). RA is a chronic inflammatory disease in which both genetic and environmental factors are involved. The precise molecular mechanisms underlying RA are not fully understood. A systematic literature search revealed nine array-based expression profiling studies in patients with RA. Findings from these studies were compared with those of linkage and genome-wide association (GWA) studies. Although we observed many differences in study design, analysis and interpretation of results between the different studies, we extracted two sets of genes: (1) those differentially expressed in more than one study, and (2) genes differentially expressed in at least one of the reviewed studies and present in RA linkage or GWA loci. We suggest that both sets of genes include interesting candidate genes for further study in RA.     

In vitro oxidations of low-density lipoprotein and RAW 264.7 cells with lipophilic O(3P)-precursors

A beneficial property of photogenerated reactive oxygen species (ROS) is the capability of oxidant generation within a specific location or organelle inside a cell. Dibenzothiophene S-oxide (DBTO), which is known to undergo a photodeoxygenation reaction to generate ground state atomic oxygen [O(³P)] upon irradiation, was functionalized to afford localization within the plasma membrane of cells. The photochemistry, as it relates to oxidant generation, was studied and demonstrated that the functionalized DBTO derivatives generated O(³P). Irradiation of these lipophilic O(³P)-precursors in the presence of LDL and within RAW 264.7 cells afforded several oxidized lipid products (oxLP) in the form of aldehydes. The generation of a 2-hexadecenal (2-HDEA) was markedly increased in irradiations where O(³P) was putatively produced. The substantial generation of 2-HDEA is not known to accompany the production of other ROS. These cellular irradiation experiments demonstrate the potential of inducing oxidation with O(³P) in cells.

Lipophilic O(³P)-precursors generate 2-hexadecenal upon UV-irradiation.